Abstract: The effect of diethylstilbest rol on urethan2induced mouse lung tumorigenesis was assessed by a single int raperitoneal injecting of urethan (500mg/ kg) or/ and multi int ramuscular injecting of diethylstilbest rol (5mg/ kg or 50mg/ kg) . All mice were sacrificed 18 weeks after administ ration , and the lung tumors were examined histopathologically. Diethylstilbest rol did not produce an elevated lung tumor response when administered alone , but it produced a statistically significant enhancement of incidence of tumors , average number of tumors , incidence of cancers and constituent ratio of malignant tumors when given in conjunction with urethan. The resul s indicated that diethylstildest rol may be a promoter in lung tumor formation.

Key words: diethylstilbest rol, urethan, lung tumor